It is known to identify objects by fitting them with labels called electronic labels which include a radio-wave aerial associated with an electronic circuit. The latter includes at least a memory containing the characteristics for identifying the object. An interrogation device transmits, using its radio-wave aerial, interrogation messages to the electronic labels and receives messages in response from the latter containing the information requested. These interrogation and response messages are transmitted according to a procedure called “anti-collision” in such a way as to make the electronic labels send out their response messages at different times.
One such system for identifying objects works in a satisfactory manner when the electronic labels are far enough away from one another. In effect, in the case of electronic labels that are very close to one another, for example, when arranged on sheets stacked one on top of the other, the tuned circuits of the different aerials are put out of tune with respect to the central F0 frequency for presenting resonance frequencies lower than and higher than F0. The result of this is that the transmission of the messages is disrupted, which leads to identification faults. One such malfunction has been noted when the objects are thin books which are stacked together on a shelf vertically or horizontally.
It would therefore be advantageous to provide a transmission/reception radio-wave aerial for an interrogation device for electronic labels carried by the objects to be identified which allows the electronic label to be interrogated whatever the distance may be that separates them.